FRIDAY, Dec. 11, 2015 (HealthDay News) -- People with asthma may be more than twice as likely to develop chronic migraines as those without breathing troubles, a new study suggests.

The research included about 4,500 Americans. At the start of the study in 2008, the study volunteers had fewer than 15 migraines a month. One year later, the researchers looked to see how many had chronic migraine -- 15 or more migraines a month.

More than 5 percent of people with asthma developed chronic migraine. Just 2.5 percent of those without asthma ended up with chronic migraines, the study found.

"If you have asthma along with episodic or occasional migraine, then your headaches are more likely to evolve into a more disabling form known as chronic migraine," said lead author Dr. Vincent Martin. Martin is a professor of medicine and co-director of the Headache and Facial Pain Program at the University of Cincinnati.

But, while the study found a link between asthma and chronic migraines, it wasn't designed to prove a cause-and-effect relationship between these conditions.

Still, the strength of the relationship between asthma and chronic migraine was robust, Martin said in a university news release. And, he added that having asthma was an even stronger predictor of chronic migraines than depression. Other research has found depression to be a strong predictor of chronic migraine, he explained.

"Migraine and asthma are disorders that involve inflammation and activation of smooth muscle either in blood vessels or in the airways," study co-author Dr. Richard Lipton, director of Montefiore Headache Center in New York City, said in the news release. "Therefore, asthma-related inflammation may lead to migraine progression."

Migraine affects about 12 percent of Americans, the researchers said. About 1 percent have chronic migraine, they added.

Prescribing preventive medications at an earlier stage to people with occasional migraine may help reduce the risk of progression to chronic migraine, Martin said.